Carb loading is one of the most well-researched performance interventions in endurance sports — and one of the most consistently misunderstood. Eating a large plate of pasta the night before your marathon is not carb loading. It is one meal that partially refills glycogen stores you have been depleting for days. Real carb loading starts three days out and requires hitting specific gram-per-kilogram targets across every meal.

This guide gives you the full three-day meal plan: specific foods, approximate gram targets, and what to cut out from each day forward.

What 3-day carb loading actually means

The goal of carb loading is to saturate your muscle and liver glycogen stores beyond their baseline capacity. Research consistently shows that a three-day protocol can increase stored glycogen by 20–40% above normal, extending the time to glycogen depletion during a marathon or long triathlon by 15–30 minutes.

The target range is 10–12 grams of carbohydrate per kilogram of bodyweight per day across the three-day loading window. For a 70 kg athlete, that means 700–840 grams of carbohydrate each day. This is more food than it sounds like — you need to be intentional about every meal.

The rules that apply across all three days: cut fiber aggressively, reduce fat to moderate levels, and eat nothing unfamiliar. Your gut is not your enemy here, but you can make it one by loading it with foods it has to work hard to digest.

Day 3 (72 hours out): building the base

Day 3 is your first real loading day. Training should be reduced to short, easy movement only — a 20-minute easy jog or a light swim at most. You are not trying to deplete glycogen on this day; you are trying to start filling it.

Target: 8–10 g carbs per kg bodyweight.

  • Breakfast: Large bowl of white rice (80g dry weight, ~60g carbs), banana (25g carbs), 200ml orange juice (20g carbs), white toast with jam (30g carbs). Total: ~135g carbs.
  • Snack: Two white bread rolls with honey (50g carbs), sports drink 500ml (30g carbs). Total: ~80g carbs.
  • Lunch: Large white pasta portion (100g dry weight, ~75g carbs), simple tomato sauce — no cream, no heavy oils (10g carbs), white bread roll (25g carbs). Total: ~110g carbs.
  • Snack: White bagel with jam (50g carbs), banana (25g carbs). Total: ~75g carbs.
  • Dinner: Large white rice portion (100g dry weight, ~80g carbs), grilled chicken breast (0g carbs), simple sauce from low-fiber vegetables like courgette (10g carbs). Total: ~90g carbs.
  • Evening: White toast with jam (30g carbs), sports drink 500ml (30g carbs). Total: ~60g carbs.

Day 3 running total for a 70 kg athlete targeting 560–700g: approximately 550g. Adjust portions up slightly if your bodyweight is higher.

Day 2 (48 hours out): peak loading

Day 2 is your heaviest carbohydrate day. Training should be minimal — 10–15 minutes of light movement maximum. Your muscles have the most capacity to absorb glycogen now, and you want to push the upper end of the target range.

Target: 10–12 g carbs per kg bodyweight.

  • Breakfast: White rice porridge made with water (100g dry rice, ~80g carbs), honey stirred in (20g carbs), banana (25g carbs), 200ml apple juice (25g carbs). Total: ~150g carbs.
  • Mid-morning: Large white bagel with jam (60g carbs), sports drink 500ml (30g carbs). Total: ~90g carbs.
  • Lunch: Large white pasta (120g dry, ~90g carbs), simple tomato and tuna sauce (10g carbs), white bread (25g carbs). Total: ~125g carbs.
  • Afternoon: Rice cakes with honey (40g carbs), 500ml sports drink (30g carbs). Total: ~70g carbs.
  • Dinner: Large white rice (120g dry, ~95g carbs), simple protein (chicken or fish), low-fiber sauce (5g carbs). Total: ~100g carbs.
  • Evening: White bread with jam (40g carbs), banana (25g carbs), 200ml orange juice (20g carbs). Total: ~85g carbs.

Day 2 running total: approximately 620–700g carbohydrate. You will feel uncomfortably full and heavier than normal. This is expected. Each gram of glycogen stored binds roughly 3 grams of water, which is why athletes gain 1–3 kg during a proper load. This weight works for you in the race.

Cut all fibrous vegetables, salads, legumes, and whole grains from this point forward.

Day 1 (race eve): top up and settle

Your glycogen stores are largely full after Day 2. Race eve is about topping them off without overloading your gut. Eat familiar foods, finish dinner early, and keep portions moderate.

Target: 8–10 g carbs per kg bodyweight.

  • Breakfast: White toast with jam (40g carbs), banana (25g carbs), 200ml orange juice (25g carbs). Total: ~90g carbs.
  • Snack: White rice cakes with honey (40g carbs), sports drink 500ml (30g carbs). Total: ~70g carbs.
  • Lunch: White pasta or rice (80g dry, ~60g carbs), simple protein, light sauce (10g carbs). Total: ~70g carbs.
  • Afternoon: White bagel with honey (50g carbs), 200ml fruit juice (25g carbs). Total: ~75g carbs.
  • Dinner (finish by 6–7pm): White rice or pasta (80g dry, ~65g carbs), chicken or fish, simple low-fiber sauce (5g carbs). Total: ~70g carbs.
  • Evening: White toast with jam (30g carbs), banana (25g carbs). Total: ~55g carbs.

Race eve total: approximately 430–500g carbohydrate. Less than Day 2 on purpose. A massive dinner on the night before the race is a common mistake — your glycogen stores are already full, and overeating late means waking up with food still in your stomach. Eat your dinner early and keep it moderate.

Foods to avoid during the loading window

The list of foods to cut during carb loading is as important as the foods to eat:

  • High-fiber foods: whole grain bread, brown rice, oats, bran, legumes, lentils, most raw vegetables, fruit with skins. These slow digestion and increase GI distress risk at race pace.
  • High-fat foods: cheese, cream sauces, fried food, avocado, fatty meats. Fat slows gastric emptying and reduces carb absorption efficiency.
  • Cruciferous vegetables: broccoli, cauliflower, Brussels sprouts. Gas-producing and fibre-heavy.
  • Alcohol: impairs glycogen synthesis and sleep quality. Avoid from Day 3 onward.
  • New foods: anything you have not eaten before a hard training session. Race week is not the time to experiment.

Use the carb-loading planner

The meal targets above are for a 70 kg athlete. Your targets will differ based on your bodyweight and your specific race. The carb-loading planner calculates your exact gram-per-day target and breaks it down by meal based on your weight and race distance. It takes about two minutes to run.

Frequently asked questions

How many carbs should I eat when carb loading? The evidence-based target is 10–12 g of carbohydrate per kg of bodyweight per day on your heaviest loading days (Day 2 and Day 3 before the race). For a 70 kg athlete that is 700–840 g per day. Race eve drops to 8–10 g/kg.

Can I carb load for a half marathon? A full three-day carb loading protocol is typically reserved for events over three hours. For a half marathon, a modified one-day approach — 6–8 g/kg the day before — is usually sufficient. The full protocol adds meaningful benefit when you need it: marathon distance and beyond.

What foods are best for carb loading? White rice, white pasta, white bread, bagels, bananas, fruit juice, honey, jam, and sports drinks. The key is low fiber and low fat — not just high carbohydrate. Brown rice and whole wheat pasta carry too much fiber to be optimal loading foods.

Should I eat pasta the night before a marathon? Pasta is fine on race eve, but it is not the most important meal of your loading window — Day 2 is. A moderate portion of white pasta for dinner works well. A massive pasta feast at 9pm the night before the race is counterproductive.

Will carb loading make me gain weight? Yes — typically 1–3 kg. Glycogen binds water at roughly 3:1, so storing an extra 400–600 g of glycogen adds 1.2–1.8 kg of water. This is not fat. It disappears during the first 60–90 minutes of the race and represents stored fuel working for you.